This invention relates to a method for producing liquid fertilizer.
Conventionally, the treatment of human feces and urine or other wastes in a sludge form has necessitated a huge amount of expense.
The water content of raw material made of human waste consisting of feces and urine is approximately 97 percent. Thus, the moisture or vapor produced by burning the raw material includes malodors. Accordingly, the moisture is drained by way of an expensive deodorizing treatment and thereafter is discharged into the river or sea.
Sewage sludge, garbage discharged from a kitchen, garbage from a food plant, or waste made of internal organs, bones, and blood from animals or fish also requires a considerable expense for the treatment thereof, since the treatment varies according to the kind of raw material and each treatment is cumbersome and time-consuming.
Eventually, the treatment of the raw material produces primarily a powdery solid fertilizer or forage so that production of a liquid fertilizer further necessitates a separate or additional liquefying treatment.
Also, since the treatment of the raw material made of human waste requires a considerable expense, the scattering of the raw material in the ocean is still continuing.
Accordingly, there is a need for a method which can effectively treat the raw material made of human waste.
It is an object of this invention to provide a method for producing liquid fertilizer characterized in that raw material made of human waste consisting of feces and urine is made to come into contact with heated animal oil, plant oil, mineral oil or a mixture of these oils under a reduced pressure, and water contained in the raw material is evaporated from the raw material and moisture made of evaporated water is collected, cooled and liquefied to produce liquid fertilizer.
It is another object of the present invention to provide a method for producing liquid fertilizer characterized in that sewage sludge, garbage discharged from a kitchen, garbage from a food plant, or waste made of internal organs, bones, and blood from animals and fish is made to come into contact with heated animal oil, plant oil, mineral oil or a mixture of these oils under a reduced pressure, and water contained in the raw material is evaporated from the raw material and moisture made of evaporated water is collected, cooled and liquefied to produce liquid fertilizer.
In this invention, approximately 1000 kg of raw material made of human waste consisting of feces and urine is charged into a cooker having a capacity of 7 m.sup.3 which preliminarily stores approximately 800 kg of animal oil, plant oil or mineral oil heated at a temperature of 70.degree. C.-150.degree. C.
Simultaneously, or after a lapse of a predetermined time (approximately 1 hour and a half to 3 hours), the pressure of the inside of the cooker is reduced (from the normal pressure to approximately 500 to 700 mmHg).
As a result of heating and reduction in pressure, the water components contained in the raw material made of human waste evaporate and the vapor and fills the cooker.
The vapor is continuously extracted or taken out of the cooker and is cooled by a condenser and drained to produce liquid.
This liquid is directly used as liquid fertilizer or water soluble nitrogen is added to the liquid to produce liquid fertilizer for hydroponics. The raw material made of human waste is dehydrated making use of the oil in the cooker and the dehydrated human waste is taken out of the cooker and the oil component is removed therefrom so as to produce fertilizer or forage in a cake form containing a high percentage of protein.
Sewage sludge, garbage discharged from a kitchen, garbage from a food plant, or waste made of internal organs, blood or bones of animals also can be heated and dehydrated in the cooker in the same manner under a reduced pressure and the vapor is cooled and drained to produce liquid fertilizer. Additionally, the raw material is dehydrated to produce fertilizer or forage in a powder or cake form containing high percentage of protein.